condition mean min max ZT0-3 9.30486 8.97684 9.63288 ZT4-7 8.88356 8.88356 8.88356 ZT8-11 7.81125 7.81125 7.81125 ZT12-15 0 0 0 ZT16-19 9.59514 9.59514 9.59514 ZT20-23 9.64153 9.64153 9.64153